1. Field of the Invention
The present invention pertains to a hydrodynamic clutch device, especially to a hydrodynamic torque converter or fluid clutch, comprising a housing arrangement with a housing hub area, in which a fluid passage space is provided, which space is in fluid-exchange connection with a working fluid space in the housing arrangement and which is also in fluid-exchange connection or can be brought into such connection with a fluid passage opening preferably provided in a power takeoff element.
2. Description of the Related Art
A hydrodynamic torque converter with a housing hub area designed in this way is known from U.S. Pat. No. 5,575,363. This known hydrodynamic torque converter 10xe2x80x2, which is shown in FIG. 5, comprises a housing arrangement 12xe2x80x2, which consists essentially of a en housing cover 14xe2x80x2 and an impeller shell 16xe2x80x2. In its radially inner area, the impeller shell 16xe2x80x2 is permanently connected by welding, for example, to an impeller hub 18xe2x80x2. The impeller shell 16xe2x80x2 also carries a plurality of impeller vanes 20xe2x80x2 proceeding in a row around the circumference and forms together with them and the impeller hub 18xe2x80x2 an impeller wheel 22xe2x80x2.
In the interior space 24xe2x80x2 of the hydrodynamic torque converter 10xe2x80x2, furthermore, there is a turbine wheel 26xe2x80x2. This comprises a turbine wheel shell 28xe2x80x2, which is permanently connected in its radially inner area to a turbine wheel hub 30xe2x80x2 and which also carries a plurality of turbine wheel vanes 32xe2x80x2.
A stator 34xe2x80x2, which carries a plurality of stator vanes 38xe2x80x2 on an outer stator ring 36xe2x80x2 and which is mounted by way of a freewheel unit 40xe2x80x2 on a support element such as a hollow shaft 42xe2x80x2 so that it is free to rotate in one direction around a rotational axis A but is prevented from rotating in the opposite direction, is provided axially between the turbine wheel 26xe2x80x2 and the impeller wheel 22xe2x80x2. The hollow support shaft 42xe2x80x2 is mounted concentrically inside the impeller wheel hub 18xe2x80x2 and also surrounds concentrically a takeoff shaft 44xe2x80x2, which constitutes the power-takeoff element. This shaft is or can be connected nonrotatably to the turbine wheel hub 30xe2x80x2 by axially oriented sets of teeth and has a fluid passage opening 46xe2x80x2 in its central area around rotational axis A, the opening passing axially through this area.
A bridging clutch arrangement 48xe2x80x2 is also provided. This comprises a clutch piston 50xe2x80x2, which, in the exemplary embodiment shown, is connected in essentially nonrotatable fashion to the housing cover 14xe2x80x2 and thus to the housing arrangement 12xe2x80x2. The radially outer area of this piston can be pressed against the housing cover 14xe2x80x2 by way of an intermediate friction lining disk 52xe2x80x2. The friction lining disk 52xe2x80x2 is connected in essentially nonrotatable fashion by way of a carrier element 54xe2x80x2 to the turbine wheel 26xe2x80x2, that is, to the turbine wheel shell 28xe2x80x2.
It can be seen that the clutch piston 50xe2x80x2 is connected by way of a flexible carrier arrangement 56xe2x80x2 to an additional support element 58xe2x80x2 in such a way that it cannot rotate but is free to move in the axial direction. The support element 58xe2x80x2 is permanently attached to a housing hub, 60xe2x80x2. The clutch piston 50xe2x80x2 is supported with freedom of axial displacement on an external circumferential area of the housing hub 60xe2x80x2 by way of an intermediate sealing element 62xe2x80x2. The housing hub 60xe2x80x2, the outer circumferential area of which is permanently connected to the housing cover 14xe2x80x2 by welding, for example, also has a centering pin 64xe2x80x2, which can be inserted into a corresponding centering opening in a drive shaft (not shown). The housing hub 60xe2x80x2 has a plurality of fluid channels 66xe2x80x2 passing through it, these channels extending approximately in the radial direction toward the outside. They connect a working fluid space 68xe2x80x2 formed between the clutch piston 50xe2x80x2 and the housing cover 14xe2x80x2 with a fluid passage space 70xe2x80x2, formed in the radially inside area of the housing hub 60xe2x80x2 and essentially surrounded by it. Another working fluid space 72xe2x80x2, which is formed essentially between the clutch piston 50xe2x80x2 and the impeller wheel shell 16xe2x80x2, and which also contains the turbine wheel 26xe2x80x2, can be supplied with working fluid through, for example, a ring-shaped intermediate space 74xe2x80x2 formed between the support element 42xe2x80x2 and the takeoff shaft 44xe2x80x2. The working fluid space 68xe2x80x2 is supplied with working fluid through the central fluid passage opening 46xe2x80x2 of the takeoff shaft 44xe2x80x2, the fluid passage space 70xe2x80x2, and the fluid passage channels 66xe2x80x2. Of course, the working fluid can also be carried away from the working fluid spaces 68xe2x80x2 and 72xe2x80x2 through the same fluid flow routes just described. By the appropriate supply and removal of fluid, a fluid pressure can be built up on either axial side of the clutch piston 50xe2x80x2. In accordance with the pressure difference thus obtained, the clutch piston will then move toward the housing cover 14xe2x80x2 to produce the bridging condition or away from it.
It can be seen that the fluid passage space 70xe2x80x2, which ultimately is produced by the formation of an axial recess in the housing hub 60xe2x80x2, which is made from a casting, for example, is sealed off on its axially open side in a fluid-tight manner with respect to the working fluid space 72xe2x80x2 by a sealing element 76xe2x80x2 installed between the turbine wheel hub 30xe2x80x2 and the housing hub 60xe2x80x2 and with respect to the space 74xe2x80x2 by a sealing element 78xe2x80x2, acting between the turbine wheel hub 30xe2x80x2 and the takeoff shaft 44xe2x80x2.
In order produce the bridging condition in hydrodynamic torque converters of this type, it is therefore necessary to build up a positive pressure in the working fluid space 72xe2x80x2; that is, the clutch piston 50xe2x80x2 must be displaced in the axial direction, and as this happens the working fluid present in the working fluid space 68xe2x80x2 is forced radially inward against the action of the centrifugal force and thus passes through the fluid channels 66xe2x80x2 and the fluid passage space 70xe2x80x2. From there it enters the fluid passage opening 46xe2x80x2 and finally arrives in a collecting pan. Because the housing arrangement 12xe2x80x2 and thus also the housing hub 60xe2x80x2 rotate during this process, turbulence or vortices are produced by Coriolis forces in the working fluid emerging from the radially inner terminal areas 80xe2x80x2 of the fluid channels 66xe2x80x2; this turbulence impedes the entry of the fluid into the fluid passage opening 46xe2x80x2 and thus increases the flow resistance of the fluid.
It is the object of the present invention to improve a hydrodynamic torque converter of the general type in question so that it is possible with a low-cost design essentially to eliminate the impediment to the free flow of the fluid in the area of the housing hub arrangement caused by the flow conditions which develop during rotation.
This object is accomplished in accordance with the invention by a hydrodynamic clutch device, in particular a hydrodynamic torque converter or fluid clutch, comprising a housing arrangement with a housing hub area, where, in the housing hub area, a fluid passage space is provided, which is in fluid-exchange connection with a working fluid space in the housing arrangement, and which also is in or can be brought into fluid-exchange connection with a fluid passage opening preferably provided in a power takeoff element.
It is also provided that at least certain areas of the fluid passage opening are divided into chambers arranged around the circumference.
By subdividing the fluid passage area into several chambers arranged around the circumference, it is ensured that, especially while the assembly is rotating, the working fluid entering the fluid passage space enters the chambers and ultimately, by virtue of its presence in certain chambers, is carried along with the circumferential motion, because these chambers are obviously rotating along with the overall assembly. It is therefore impossible for any fluid turbulence to develop essentially unhindered around the rotational axis A, which turbulence could impede the entry of the fluid into the fluid passage opening of the takeoff element.
For example, a partition arrangement can be provided, by means of which the spaces are separated from each other at least in the circumferential direction. This partition arrangement or various wall sections thereof ultimately fulfill the function of vanes, which then carry along the fluid entering the various chamber areas as they rotate and thus prevent the development of turbulence.
The partition arrangement can consist, for example, of a single partition element, which is installed in the fluid passage space. This partition element, at least one of which is present, can be designed essentially in the form of a xe2x80x9cUxe2x80x9d with a connecting web area which is or can be positioned after the takeoff element in the axial direction, from which web area two essentially axial sidepiece sections proceed, which are designed to extend at least partially over the takeoff element in the axial direction. Ultimately to prevent the formation of turbulence or vortices around the rotational axis A until the fluid enters the fluid passage opening, a latching projection for axial engagement with the fluid passage opening of the takeoff element is provided on the connecting web area.
In the hydrodynamic clutch device according to the invention, the partition arrangement can be fixed in position on the housing hub area by a method such as caulking, welding (preferably resistance welding), or latching.
A connection of the partition arrangement to the housing hub arrangement which is very easy to produce and cheap to manufacture can be obtained by providing on the housing arrangement a plurality of fluid passage channels for establishing the fluid-exchange connection between the fluid passage space and the working fluid space and by providing the partition arrangement with at least one latching projection, which is or can be latched into one of the fluid passage channels to establish the latched connection.
To be able to provide the effect intended by the partition arrangement as effectively as possible, it is proposed that the partition arrangement rest essentially completely against an inside surface of the housing hub area which surrounds the fluid passage space.
A very low-cost design can be obtained by forming the partition element, at least one of which is provided, out of sheet metal, preferably out of spring sheet material.
The flow resistance in a hydrodynamic clutch device according to the invention can be minimized even more by providing a plurality of fluid passage channels in the housing arrangement for establishing the fluid-exchange connection between the fluid passage space and the working fluid space and by installing the partition arrangement in the housing hub area circumferentially between two fluid passage channels in each case, i.e., between the areas where the channels open out into the fluid passage space.
Other objects and features of the present invention will become apparent from the following detailed description considered in conjunction with the accompanying drawings. It is to be understood, however, that the drawings are designed solely for purposes of illustration and not as a definition of the limits of the invention, for which reference should be made to the appended claims. It should be further understood that the drawings are not necessarily drawn to scale and that, unless otherwise indicated, they are merely intended to conceptually illustrate the structures and procedures described herein.